The invention relates to an apparatus for the scanning of a profile.
The scanning of a profile, e.g. a cross-sectional profile of an article, has many practical applications, and is therefore used within many technical areas, e.g. in connection with production control, the measurement of wear and the like.
The present invention has been developed for the measuring of the cross-sectional profile of train wheels and rails, and is thus described in connection herewith, even though it will be obvious to those familiar with the art that the apparatus according to the invention can be used for the scanning of surfaces or profiles on many other articles and items.
In the operation of railways, the cross-sectional profiles of the wheels and the rails are of great importance for a train's vehicular dynamics, and herewith for the train's security, comfort and operational economy. During operation, the wheels and rails become worn, which results in increased risk of breakage and derailments, accelerated wear and a reduction in the running characteristics of the wheels. Worn wheels and rails result in increased dynamic forces during operation, a reduction in comfort and a further acceleration of the wear. By regular investigation of wheels and rails, especially their cross-sectional profiles, there can be established a systematic and condition-determined maintenance, and the operational costs are considerably reduced. However, a large part of the maintenance of rolling stock still takes place on the basis of measurement of operating time and operational distance, rather than on a systematic supervision of conditions.
It is known to measure the cross-sectional profile of an article, for example a train wheel, cf. e.g. European patent application no. 0.252,164 or German publication no. 3.637.839. These known apparatus are complicated and timeconsuming to use, in that they must be mounted firmly on or at the wheel while a measurement of the wheel profile is carried out, and it is particularly complicated to calculate the result of the measurement and evaluate how the machining and the renovation of the wheel is to be implemented. Consequently, many of the known types of apparatus are arranged for workshop use, i.e. when the relevant railway carriage has already been taken out of operation.
From European patent application no. 0.155,084 it is known to scan or measure the profile of a three-dimensional article with an apparatus which is configured substantially as disclosed in the preamble to claim 1. However, this apparatus can only measure convex surfaces and curves due to the configuration of the scanning probe, and because the electronic circuit associated with the apparatus is not arranged herefor.